We derive fundamental, structural, and photometric parameters of 15
overlooked Ruprecht (hereafter Ru) star clusters by means of 2MASS photometry
and field-star decontamination. Ru\,1, 10, 23, 26, 27, 34, 35, 37, 41, 54, 60,
63, 66, and 152 are located in the third Galactic quadrant, while Ru\,174 is in
the first. With the constraints imposed by the field-decontaminated
colour-magnitude diagrams (CMDs) and stellar radial density profiles (RDPs), we
derive ages in the range 400\,Myr --- 1\,Gyr, except for the older Ru\,37, with
∼3\,Gyr. Distances from the Sun are within \rm1.5\la\ds(kpc)\la8.0. The
RDPs are well-defined and can be described by a King-like profile for most of
the radial range, except for Ru\,23, 27, 41, 63, and 174, which present a
conspicuous stellar density excess in the central region. The clusters dwell
between (or close to) the Perseus and Sagittarius-Carina arms. We derive
evidence in favour of cluster size increasing with distance to the Galactic
plane (\zgc), which is consistent with a low frequency of tidal stress
associated with high-|\zgc| regions. The clusters are rather faint even in
the near-infrared, with apparent integrated \jj\ magnitudes within 6.4\la
m_J\la9.8, while their absolute magnitudes are -6.6\la M_J\la-2.6.
Extrapolation of the relation between MV and MJ, derived for globular
clusters, suggests that they are low-luminosity optical clusters, with -5\la
M_V\la-1.Comment: The paper contains 11 figures and 3 tables. Accepted by MNRAS
